90 FWB 307
So after I fixed my fan belts and brake lines, the head gasket goes. I drive it home from work and its smoking under the hood. Looking under the hood and its pissing on the fan. Further look and its squirting out of the head right in the front, easy to see. So my first thought was "lets put a caddy 500 in this thing" but now I like how Dopestar's car sounds now that its back. I would love to throw a 500hp BBC in here but it would be easier and cheaper to rebuild the 307. My delima is that once I get the 307 out, I'm gonna want to put something else in there. So do yall think I should go with a 307, 454 or 500? I like the 307 because its original. I like the 454 because its made to handle some weight. The 500 because its my dream motor. What to do?

jayoldschool

11-17-08, 11:23 PM

Since you want to replace it, why not go with something from the Olds family, but bigger? You have the choice of the 350, the 403, and the mighty 455. Plenty of parts for all of them. And, they will bolt right to everything in your car. All your accessories will work, too. One note: the tall deck on the BB (403/455) may cause clearance problems with the HVAC bulge on the passenger side firewall. NODIH will likely know...

Personally, I would go for a 403. Won't be expensive like a 455, but will make a boat load of torque to push that Caddy:thumbsup:

csbuckn

11-17-08, 11:59 PM

I was thinking the 455 but isnt that motor made more for racing? Thats why I thought the 454 truck motor, more for torque, right? even though if I did the 350, I could use the tranny and save a million bucks. Now I think I may go with the olds 350, just less headache and worth taking the motor out.

Or a little more new school . . .
Supercharged LS7 750hp, 680lbs torque, more if you turn up the boost
http://www.katechengines.com/street_performance/engine_packages.php

dirt_cheap_fleetwood

11-18-08, 01:07 PM

Go to the junkyard and get an old 350 block. Rebuild it right with a good cam and higher compression and you will easily hit 400 hp on 93 octane.

I~LUV~Caddys8792

11-18-08, 02:32 PM

I like the 403...too bad they never offered one with Fuel Injection. I drove a '78 Toronado Brougham with a 403, and it offered more than adequate power in that yacht...and the Brougham weighs probably 600 lbs less.

Or a little more new school . . .
Supercharged LS7 750hp, 680lbs torque, more if you turn up the boost
http://www.katechengines.com/street_performance/engine_packages.phpSo which of the two motors are in your '91?.

jayoldschool

11-18-08, 07:44 PM

I was thinking the 455 but isnt that motor made more for racing? Thats why I thought the 454 truck motor, more for torque, right? even though if I did the 350, I could use the tranny and save a million bucks. Now I think I may go with the olds 350, just less headache and worth taking the motor out.

The 455 came in plenty of full size four doors and station wagons. They just don't get remembered like 442s!

Your stock trans will bolt to any of the engines I mentioned. If you drive like a maniac, it won't last long behind a high output motor, though.

I would just start shopping around, and see what you can find. A 350, 403, or a 455 would all be nice choices. Don't be afraid to buy a whole car, and just grab the engine for your car. Often, this can be cheaper than buying an engine alone from a yard. Plus, you can see how the engine runs, and you can part the rest of the car and make some money! Also, you will get about 300 bucks for scrap value for the car when you are done with it...

csbuckn

11-19-08, 12:59 AM

now I'm torn between the 350 and the 455. Would the stock accessories bolt on the 455? But I cant bolt that 200 behind a built 455, because if I rebuild one, it wont be stock. I also have a chevy 400 tranny in my garage that I was gonna try my first rebuild on, cant I just get an adapter? Oh, the choices...

csbuckn

11-22-08, 12:58 AM

So after looking on craigs, I notice a few 400cu motors. Are these Olds motors or pontiac? Are Olds and Pontiac motors the same thing? Would my accessories bolt up to them?

deVille33

11-24-08, 11:11 PM

Sorry, Pontiac is a whole other animal. Personally, I'd use the 350. The 350 is a pretty nice engine. produces good performance and will out-torque your SBC. It will take up a little more room in your engine compartment, but it should fit. There are also several performance parts available for the 350.

csbuckn

12-13-08, 01:18 PM

got an olds 350, should be an exact fit right. all my computers are down and im on my friends G1 phone but will look when i get a chance

VortecCaddy

12-13-08, 02:51 PM

I say go for the 500 rat motor. I am gonna be doing this over the winter also.

csbuckn

12-14-08, 10:08 PM

I would have loved to get the 500 but the olds 350 was only 50 bucks so I said hell yea. I been watchin too much pinks so I need to build something like that in the summer.

cadillac_al

12-15-08, 10:47 AM

$50 is dirt cheap. You should change the plastic coated timing gears while you have it out and clean the broken plastic pieces out of the oil pickup if it hasn't been done yet. If you could afford an Edelbrock Performer cam and lifters you would be a happy man.

csbuckn

12-17-08, 07:12 PM

I have been thinking about what cam to go with. The other caddy has a stage one melling cam and it still idles smooth. I was thinkingto go bigger this time. But then they say maybe no power brakes so probably stick with the smaller cam. No egr or smog also. And an aftermarket intake manifold. Anybody find some headers that would fit yet, my first try didn't fit.

cadillac_al

12-18-08, 12:42 PM

Olds has wimpy non-adjustable rocker arms. That's why I recommended the Edelbrock cam because it will work with the stock valve train. Stock GM cams are so tame that any moderate cam is a big improvement.

csbuckn

12-21-08, 05:28 PM

So I got the motor on the stand and apart. When I took the heads off, all you could smell is burnt oil. Havent made it to the crank and cam yet but maybe later, I dont have heat or electricity in the garage so I have to thaw out while I watch the Vikings game.

csbuckn

12-21-08, 06:52 PM

So now I'm stuck on what cam to go with. The hassle free one would be the RV/torque cam which is the one step up from stock. Or go with 2 steps up, which would need headers and intake. It also says to go with smaller gears in the rear but what would happen if I dont get the smaller gears?

csbuckn

01-05-09, 01:05 AM

Its late and I'm tired but cant make up my mind on which way to go with the olds 350 rebuild. I'm starting to lean towards a basic cam upgrade, new lifters, timing set(no plastic pieces), ROLLER ROCKERS?, H-pipe insert, and stock intake manifold with a carb spacer. I read alot about roller rockers adding 15-30hp and keeping the valve train quite, what do yall think

jayoldschool

01-05-09, 07:38 PM

The talk about 15hp for roller rockers is for full rollers, not just roller tips. Something like the Crane Pro Mag...

csbuckn

01-12-09, 02:05 PM

This isnt normal! Pulled this off the 350 I bought(ROD bearing!). Crank is pretty bad too. So when I get the machining done on the block, they have a way of cleaning out all the shavings in the passages, right?

csbuckn

01-14-09, 02:11 AM

So now I have a question for the engine builders out there. I've been doing alot of research on the olds motor and what I've come up with is this. I'll probably go high compression on this and see that the heads I have with the olds 350 are 75cc and the heads from the '90 307 are 67cc's. Can I put the heads from the 307 on the 350 with some HC pistons? Is this gonna be driveable as a daily driver? One thing I do read is that the 77 block(which I bought) have 1/2 inch bolt holes, will this make the 307 heads not fit?

deVille33

01-15-09, 10:46 PM

This isnt normal! Pulled this off the 350 I bought(ROD bearing!). Crank is pretty bad too. So when I get the machining done on the block, they have a way of cleaning out all the shavings in the passages, right?

Right, It would be a good idea to have the block hot tanked, and all the inner passages opened and cleaned out also.
Badly spun rod bearing. You'll need another rod and you should have the crank ground or replaced.
Check all your rods for big end size. Pay special attention to your rod bolts. If you plan on building up this engine for more performance, as you seem to be heading, concider replacing the rod bolts and resizing all rods.

deVille33

01-15-09, 11:07 PM

So now I have a question for the engine builders out there. I've been doing alot of research on the olds motor and what I've come up with is this. I'll probably go high compression on this and see that the heads I have with the olds 350 are 75cc and the heads from the '90 307 are 67cc's. Can I put the heads from the 307 on the 350 with some HC pistons?

307 heads will not interchange with 350. 307 block is a smaller version of the 350. Deck surface for 307 block is shorter.

Is this gonna be driveable as a daily driver? One thing I do read is that the 77 block(which I bought) have 1/2 inch bolt holes, will this make the 307 heads not fit?

You have to concider that today's gas is not a great supporter of higher combustion pressures. You can go to perhaps 9.5 to 1 to run 87 octane. 10:1 and you need at least the 93 octane rated fuel. Beyond that your going to need 102 racing fuel.

csbuckn

01-16-09, 01:05 AM

I usually run on 93 octane after a build but after a little digging, I found that the stock 85-90 307 7A heads have tiny intake and exhaust ports so they dont have good flow through. So I have to stick to the 75cc heads I got with the 350. The 307 heads will fit but the ports are so small that aftermarket intake or exhaust would not seal that great. I may still take them off and compare the two before deciding.

csbuckn

02-08-09, 03:34 AM

Just an update...The engine I bought had a cracked head so I ended up with two more olds 350s dated 73 and 77(the guy said I had to take both or none). The 73 has the solid main webs but I already had the machine work done to the windowed block I have so I'll probably stick with it. I'm glad he told me to take both because I was just going to take the 73 thinking it was better but the 77 had better heads and bigger exhaust manifolds. The new heads are going in for machining tomorrow. Until next time...